Old school thinking and possessive ML.

Not sure if you're only looking for romcoms, but here are a variety of dramas with possessive ML dramas. I watched more kdramas so there will be more of them (in no particular order).

Modern setting

• Meteor Garden - all adaptations lol

Kdramas

• The World of the Married
  
• Secret 
• Jealousy Incarnate
• Another Miss Oh
• Mask
• The Last Empress
• New Tales of Gisaeng
• Cheese in the Trap 
• Que Sera Sera
• What Happened in Bali 
• Giant - the secondary couple 

Cdramas/Twdrama

• I Love My President Though He's a Psycho 
• My Sunshine 
• Well-Intended Love
• Love O2O
• Before We Get Married
• It Started With a Kiss?

Historical and period dramas

Kdrama

• Empress Ki 
• Moon Lovers
• Jang Ok Jung?
• Chuno
• Damo
• The King in Love
• My Country - possessive bromance
• Queen for Seven Days - the second ML is VERY possessive and controlling
• Tale of Nokdu - the second ML

Cdrama/Twdrama

• Too Late to Say I Love You 
• Siege in Fog 
• Goodbye My Princess 
• Bloody Romance - the second ML
• Ashes of Love - the second ML becomes increasingly more possessive and controlling

 sobak:

Not sure if you're only looking for romcoms, but here are a variety of dramas with possessive ML dramas. I watched more kdramas so there will be more of them (in no particular order).

Modern setting

• Meteor Garden - all adaptations lol

Kdramas

• The World of the Married
  
• Secret 
• Jealousy Incarnate
• Another Miss Oh
• Mask
• The Last Empress
• New Tales of Gisaeng
• Cheese in the Trap 
• Que Sera Sera
• What Happened in Bali 
• Giant - the secondary couple 

Cdramas/Twdrama

• I Love My President Though He's a Psycho 
• My Sunshine 
• Well-Intended Love
• Love O2O
• Before We Get Married
• It Started With a Kiss?

Historical and period dramas

Kdrama

• Empress Ki 
• Moon Lovers
• Jang Ok Jung?
• Chuno
• Damo
• The King in Love
• My Country - possessive bromance
• Queen for Seven Days - the second ML is VERY possessive and controlling
• Tale of Nokdu - the second ML

Cdrama/Twdrama

• Too Late to Say I Love You 
• Siege in Fog 
• Goodbye My Princess 
• Bloody Romance - the second ML
• Ashes of Love - the second ML becomes increasingly more possessive and controlling

Hey! Thanks for so many recommendations! Really appreciate it. I have already watched some of them but not all. 

I am interested in Mask though, is  main hero really jealous and possessive ? ^_^ 

 sobak:

I wouldn't be surprised if you've seen a lot of it lol They don't really make as many crazy possessive/controlling MLs anymore.

He is not toxic like some of the other MLs. He gets obsessed with the FL because she is the first person who really sees him for who he is and doesn't treat him like the psycho/black sheep/stain on family's name. Now that I think about it...maybe he isn't exactly what you're looking for lol but he only has eyes for the FL, and will do anything for her.

Oh ok. You are right there are so few dramas with possessive lead that it frustates me. Because i really like trope. Thanks anyways ^_^ 

You've probably already seen it, but Girl in Tassel Earring! I put off watching it for so long because it looked kind of boring to me, but the main lead is crazy possessive, always grabbing the female lead, telling her she can't do anything without telling him, at one point telling his guards not to let her leave.